Welcome to Professional and Technical Services (PTS) – experts in chemical disinfection for infection prevention. Our goal is to educate and provide you the latest resources related to cleaning and disinfection of environmental surfaces, medical devices and hands. As specialists in disinfectant chemistries, microbiology, environmental cleaning and disinfection, facility assessments and policy and procedure creation we are dedicated to helping any person or facility who uses chemical disinfectants.

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Thursday, April 25, 2019

Spring Cleaning - Fridges, Freezers and Cryostats

There are some who really fancy a good
spring clean. Whether it’s purging your closets with clothes you no
longer wear, cleaning out the fridge of expired food or your freezers ancient
relics of freezer burned food, you will find that there is something cathartic
about cleaning and purging.

I suspect that many have not considered how
to clean and disinfect cold surfaces like the inside of a fridge, a freezer or
even a cryostat for example. Disinfection is all about contact
time - the length of time the surface MUST stay wet to achieve the
disinfection claims as noted on the product label.For some surfaces this can be
problematic.If the surface is hot, the
disinfectant is going to evaporate well before the contact time can be
achieved. Can you imagine how quick a hot surface will flash off the product if
an alcohol based product is used?

Cold or freezing surfaces pose an entirely
different issue. How do you keep a water-based product like a disinfectant from
freezing when it comes in contact with a surface that is below freezing?The truth is it’s hard, hence the topic of
this week’s blog.

Disinfectants can come in a number of
different formats such as Ready-To-Use (RTU) Liquids, Pre-Moistened Wipes and
Concentrates that require dilution prior to use. When dealing with cold
temperatures, part of the decision you need to make is how to avoid your liquid
disinfectant from freezing so that you can apply it to the surface you need to
clean and disinfect. In this case, your only option is the use of a concentrate.

Why you ask? Well, as the name implies RTU
Liquids or Pre-moistened wipes are products that are intended to be used as
they are manufactured and packaged. They have been tested and approved for use
by the EPA, Health Canada or any other regulatory body to be used at the
concentration stated on the bottle. Doing anything to an RTU or Wipe product,
such as the addition of another chemical will dilute the product and render it
ineffective.At the very least, you’ve
changed the concentration so that the disinfectant manufacturer will not be
able to provide any proof indicating the product will still be effective or
what the contact time would be.

Concentrates on the other hand need to be
diluted prior to use. This then allows you to add propylene glycol (PG) while
diluting (usually up to 10%). Similar to how we have a Summer Windshield Washer
Fluid and a Winter Windshield Fluid, propylene glycol is added to stop the
freezing. The importance of this however, is that you need to work with your
disinfectant manufacture to verify if they have conducted testing to ensure if
you add PG that the product will not be neutralized. You also do not
necessarily want to use winter windshield washer fluid as we found it can
impact the pH and efficacy of products!

If you’re looking at spring cleaning a few
of your hard to clean devices or machines, I hope you’ll contemplate how you
used your disinfectant so that you achieve the level of kill you need!

Bugging Off!

Nicole

PS – if you’re interested check out some of our past
blogs that talk about contact time such as: